[Invited] Phononic crystal for dynamic viscosity determination: [Invited]

International audienceWe propose a two-dimensional triangular lattice solid/fluid phononic crystals (PnC) for the determination of the acoustic properties and in particular dynamic viscosity of a fluid. We show that this device is very sensitive to the acoustic parameters of the liquid, such as density or sound velocity, and could consequently be used as a temperature sensor. This temperature sensitivity is investigated through the existence of sharp waveguide acoustic modes localized in the band gap of the PnC at well-defined frequencies. We show that this device can also be used for dynamic viscosity measurements of liquid, based on the attenuation of the guided modes

Temperature biosensor based on triangular lattice phononic crystals

International audienceA two-dimensional triangular lattice solid/fluid phononic crystal (PnC) is proposed as a sensitive biosensor to detect the temperature of the Methyl Nonafluorobutyl Ether (MNE) in the range of 10-40 degrees C. Temperature changes in MNE represent an important issue for its various applications. Indeed, the MNE is widely used in cosmetic and beauty products for its non-toxic, non-flammable, and colorless chemical properties. For this purpose, a sensitive biosensor for temperature and physical properties of MNE appears necessary. The PnC biosensor consists of a triangular lattice of tungsten cylinders embedded in an epoxy background inside of which a line of hollow cylinders filled with MNE is introduced as a waveguide for guiding resonant modes with low group velocity. We show that the PnC biosensor provides sharp guided modes in the bandgap with high quality factors and frequencies depending on the MNE temperature with high sensitivity. The introduction of damping inside the liquid shows that the shear viscosity, compared to longitudinal, affects drastically the amplitude of the resonant peaks. However, the length of the waveguide can be adapted so as to recover the resonant peak in the presence of viscosities